/*
 * Copyright (C) 2007-2010 Geometer Plus <contact@geometerplus.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
 * 02110-1301, USA.
 */

package org.geometerplus.zlibrary.core.filesystem.tar;

import java.io.IOException;
import java.io.InputStream;

class ZLTarInputStream extends InputStream {
    private final InputStream myBase;
    private final String myFileName;

    ZLTarInputStream(InputStream base, String fileName) throws IOException {
        myBase = base;
        myFileName = fileName;

        ZLTarHeader header = new ZLTarHeader();
        while (header.read(myBase)) {
            if ((header.IsRegularFile) && fileName.equals(header.Name)) {
                return;
            }
            final int sizeToSkip = (header.Size + 0x1ff) & -0x200;
            if (sizeToSkip < 0) {
                throw new IOException("Bad tar archive");
            }
            if (myBase.skip(sizeToSkip) != sizeToSkip) {
                break;
            }
            header.erase();
        }
        throw new IOException("Item " + fileName + " not found in tar archive");
    }

    public int read() throws IOException {
        return myBase.read();
    }

    public int read(byte b[]) throws IOException {
        return myBase.read(b);
    }

    public int read(byte b[], int off, int len) throws IOException {
        return myBase.read(b, off, len);
    }

    public long skip(long n) throws IOException {
        return myBase.skip(n);
    }

    public int available() throws IOException {
        return myBase.available();
    }
}
